VictoriaMetrics/VictoriaMetrics · error

cannot dial socket path %q: %w

Error message

cannot dial socket path %q: %w

What it means

removePreviousSocketFile dials the existing socket path to test liveness; any dial error other than ENOENT or ECONNREFUSED (e.g. EACCES — access denied) is not safely interpretable, so it is wrapped and returned instead of unlinking the file. This prevents deleting a socket that might belong to a running process the caller cannot even probe.

Source

Thrown at lib/netutil/unixlistener.go:71

		return fmt.Errorf("file %q already exists and is not a socket", addr)
	}

	conn, err := net.DialTimeout("unix", addr, 100*time.Millisecond)
	if err != nil {
		if errors.Is(err, os.ErrNotExist) {
			// File does not exist.
			return nil
		}
		if errors.Is(err, syscall.ECONNREFUSED) {
			// File exists, but there is no listener.
			// This may happen in case of unclean shutdown, so remove it.
			if err := os.Remove(addr); err != nil {
				return fmt.Errorf("cannot remove exist socket path: %w", err)
			}
			return nil
		}
		// Could be access denied or other unrelated errors.
		return fmt.Errorf("cannot dial socket path %q: %w", addr, err)
	}
	_ = conn.Close()
	return fmt.Errorf("another process is already listening on %q", addr)
}

// UnixListener listens for the addr passed to NewUnixListener.
//
// It also gathers various stats for the accepted connections.
type UnixListener struct {
	*net.UnixListener

	accepts      *metrics.Counter
	acceptErrors *metrics.Counter

	cm connMetrics
}

// Accept accepts connections from the addr passed to NewUnixListener.

View on GitHub (pinned to 5079fb58f1)

Solutions

1. Inspect the wrapped %w error (often 'connect: permission denied')
2. Fix permissions so the current user can access the socket path and its parent directories (chmod/chown)
3. Remove the socket file manually if you are certain no process is using it
4. Run the process under the same user that created the previous socket

Example fix

// before
$ ls -l /run/vm.sock  # srw------- root root
$ ./victoria-metrics -unixListenAddr /run/vm.sock  # EACCES
// after
$ sudo rm /run/vm.sock   # or chown/chmod so the service user can access it

import "net"
import "os"
import "time"

func socketIsAccessible(addr string) error {
	if _, err := os.Lstat(addr); err != nil {
		return nil // no file, nothing to probe
	}
	conn, err := net.DialTimeout("unix", addr, 100*time.Millisecond)
	if err != nil {
		return nil // will be handled by the library (refused/not-exist)
	}
	conn.Close()
	return fmt.Errorf("already listening on %s", addr)
}

ln, err := netutil.NewUnixListener(sockPath)
if err != nil {
	if strings.Contains(err.Error(), "cannot dial socket path") {
		var se syscall.Errno
		if errors.As(err, &se) && se == syscall.EACCES {
			log.Fatalf("no permission to probe %s; fix socket/dir ownership", sockPath)
		}
	}
	return err
}

When it happens

Trigger: NewUnixListener is called with an addr where a socket file exists but net.DialTimeout fails with a non-ENOENT/non-ECONNREFUSED error — most commonly EACCES because the current user cannot read/write the socket file or traverse its directory.

Common situations: Socket created by another user or in a directory with restrictive permissions, AppArmor/SELinux denials, or a socket under a path with no execute permission for the current user.

Related errors

• cannot set permissions for socket path %q: %w
• cannot remove exist socket path: %w
• cannot delete `backup complete` file at %s: %w
• cannot open directory: %w
• cannot append files %q: %w

AI-assisted analysis of VictoriaMetrics/VictoriaMetrics@5079fb58f1 (2026-09-03). Data as JSON: /api/errors/07ab5423e25c16d7. Report an issue: GitHub.